This invention relates generally to still image pickup apparatus, and particularly to such an apparatus and method for producing a still image video signal using a solid-state imaging device.
Still image pickup apparatus is arranged to store a video signal or a picture signal from an image-pickup device so that the picture signal corresponding to a field or frame is repeatedly read out from a memory. However, when a solid-state imaging device, such as a CCD imaging device, is used as the image pickup device, such still image pickup apparatus has hitherto been unsatisfactory because a high-quality image cannot be obtained for the following reasons.
When a solid-state imaging device is used as an image pickup device, a reproduced still picture is apt to suffer from a fixed pattern of specks due to variations in magnitude of photoelectric conversion signal resulted from scattering of reading out efficiency throughout respective pixels (picture elements) of the solid-state imaging device. Furthermore, in addition to the above reason because of variations in magnitude of photoelectric conversion signal resulted from nonlinear error caused from the scattering of transfer efficiency throughout respective pixels, nonlinear distortion occurs in dark portions in the reproduced picture. Moreover, the dark portion in the reproduced picture shows low luminance, while coloring of the dark portion occurs due to false color signals.